Continuous flow heater



P 1965 H. VIESSMANN CONTINUOUS FLOW HEATER 5 Sheets-Sheet 1 Filed Nov. 28, 1962 Sept. 21, 1965 H. VIESSMANN CONTINUOUS FLOW HEATER 3 Sheets-Sheet 2 Filed Nov. 28, 1962 Sept. 21, 1965 H. VIESSMANN 3,207,130

CONTINUOUS FLOW HEATER Filed Nov. 28, 1962 5 Sheets-Sheet 3 United States Patent 3,207,130 CONTINUOUS FLOW HEATER Hans Viessmann, im Hain, Battenherg (Eder), Germany Filed Nov. 28, 1962, Ser. No. 240,539 Claims priority, application Germany, Nov. 30, 1961, V 21,672; Jan. 12, 1962, V 21,871; Apr. 17, 1962, V 22,375

6 Claims. (Cl. 122-32) The present invention relates to tube-type heaters. More specifically, this invention relates to such heating apparatus as may be used in boilers, furnaces, flues or the like and is concerned with the arrangement of the heatexchanging tubes and the configuration of the complete heater as well as with means facilitating the operation and maintenance of the heater.

Heretofore, continuous flow heating systems have consisted of a plurality of tubes designed to permit continuous flow of the fluid medium therethrough and have been mounted in a boiler or furnace such that only the ends of the tubing are accessible from without. Such heaters may form a unit that can be mounted as a whole inside the boiler or furnace where it acts as a heat exchanger.

These units or tube batteries have substantial disadvantages, inasmuch as they are difficult to clean and their space requirements are uneconomical. Moreover, the connections or tube joints can be assembled and maintained only at the expense of substantial time. On the other hand, such maintenance is unavoidable in the continuous preparation of service water because, after certain periods of time, minerals contained in the water have deposited on the tube walls, thereby preventing the proper exchange of heat. In conventional systems, this is remedied by cleaning the heat-exchanging surfaces or ports or both. In most cases, however, this requires dismantling of the whole heater. Chemical cleaning has proved expensive and does not at, all insure actual cleaning of every inch of the tubes to a degree of fully restoring the original inner diameter of the tubes. Moreover, this conventional cleaning process is rather cumbersome and time-consummg.

It is therefore a primary object of the present invention to provide a tube-type heater system that can be simply and effectively cleaned without having to be removed from the boiler or furnace, an increase, if any, in the manufacturing cost being set off by the reduction of the heater size as compared with any well-known heater.

Another object of the present invention is to mount the tubes of the heater in such a manner as to facilitate the cleaning of each tube to its full original inner diameter without removing the heater from the boiler or furnace.

It is therefore a further object of this invention to reduce the number of types of fittings required to interconnect the tubes, so as to simplify the assembly and facilitate the quantity production of suchfittings.

A further object of the present invention is to provide means in the tubes generating a flow turbulence, such means being characterized by their ability to not hinder the tube cleaning process.

Finally, it is an object of this invention to arrange the tubes so that they require as little space as possible, without interfering with any of the other objects'of this invention.

The complete heater, although mounted in the boiler or furnace by conventional fixingmeans, is nevertheless characterized by special features peculiarto the configurations of the embodiments in accordance with the invention.

One of thesse features consists in the assembly of two tubes by a V'shaped elbow to form apairgof tubes mounted in the heater in such a way that one of the two tube ends forming, the V is connected to one box and the 3,207,130 Patented Sept. 21, 1965 other end to another box, the boxes being employed to interconnect the pairs of tubes and being covered by a cover plate common to all boxes such that the fluid medium entering one leg of the V-shaped tube pair leaves this pair by the other leg, and runs then through the associated box and from these to the first leg of the adjacent V-shaped pair of tubes, and so on.

Another feature of this invention is that each of the tubes is, in its inside, equipped with helical deflecting means mounted in a loose relation to the tube wall and ready to be withdrawn at any time.

Still another feature pertaining to the invention is the provision of helical deflecting means such that these means may be permanently attached to the inner tube walls, but are made from thin-gage sheet material so that they can be readily drilled out together with mineral deposits for the purpose of cleaning the tubes.

Other features of this invention will become apparent from the following description. Thus, it is possible to arrange the tubes in an inclined position such that no junction boxes are necessary. Instead, the upper ends of the V-shaped pairs of tubes are directly interconnected by tube fittings.

Thus, it is seen that the tubes of the present heater can be mechanically cleaned without being removed from the heater and without removing the heater from the boiler or furnace, after the helical deflecting means have been pulled out by screw-like turning, unless the deflecting means are of the type suited for being drilled out with the mineral deposits.

The aforesaid mechanical cleaning process may be performed, for instance, with the aid of a crown-bit drill. Since the lower ends of the tubes of a V-shaped pair are interconnected by a V-shaped elbow, the latter becomes accessible by the drill used in the cleaning of the tubes, because the two paths of the drill through the two legs of the V formed by the tubes intersect in the elbow thereby removing any deposit accumulated in both the tubes and the elbow of any pair. It will be appreciated that in a conventional heater where the tubes are arranged horizontally or vertically and parallel to each other rather than in a V-configuration, all the remote ends of the tubes would have to be equipped with a junction box that would become accessible only after the whole heater has been removed from the boiler or furnace.

The arrangement of the helical deflecting means inside the tubes insures good heat exchange due to the resulting guidance of the liquid flow, and no high velocity of flow is required to attain a turbulence.

To further the heat-exchange, the deflecting means may according to the invention be provided with perforations, bent-out portions etc., thereby increasing the effect produced by the continuous direction of the liquid in the tube to the heat-exchanging surfaces. Moreover, the tubes may preferably be provided with fins at their outer periphery.

Depending on the rate of flow and the liquid delivery, either single or double pairs of tubes assembled to V elements can be connected in series. Other varieties of mounting are an upper row of tubes connected in parallel andanother lower row of tubes again connected in. parallel for cases where large quantities of water or some other liquid are to be slightly heated only; or vertical or horizontal orientation of the heater tubes in accordance with the above described principles. In each such case, however, removal of the cover plate will give full access to all the upper tube ends, so that the tubes may be cleaned Without removing the heater from the furnace or boiler. The same advantage is also attained in case of the embodiment where the upper ends of the V-shaped pairs of tubes are directly interconnected by fittings. Here, only the plugs taking the place of the common cover plate have to be removed to attain the same effect.

Further details of the invention will become apparent from the following description in conjunction with the attached drawings wherein FIGURE 1 is a graphic representation of the heater according to the invention, partly sectionalized;

FIGURE 2 is a section along line II in FIG. 1;

FIGURE 3 is a section through a tube showing a perforated deflecting means according to the invention;

FIGURE 4 is a section through a tube showing a deflecting means having bent-out portions;

FIGURE 5 is a section through a tube showing a deflecting means being in contact with the tube wall at certain points only;

FIGURE 6 is a plan view of the heater, with the cover plate partly removed;

FIGURE 7 is a graphic representation and partly a section of a heater detail where the tubes are interconnected by fittings;

FIGURE 8 is a plan view of a heater, with the tubes arranged as shown in FIG. 7, and

FIGURE 9 is a plan view of a heater, with the pairs of tubes arranged in staggered relationship for low constructional height.

As can be seen from FIGS. 1 and 2, tubes 1 having fins 2 at their outer periphery are inserted in a mounting plate 3 that is reinforced by a mounting-plate frame 4. Frame 4 has through-holes 5, which permit the frame to be mounted to a furnace or boiler 1'. Moreover, frame 4 is also provided with threaded holes 6 for fastening a coverplate 7. Boiler 1 has an aperture 1" and, in fixed relation thereto, bolts 5', which, when the heater is mounted in place, engage in holes 5 in frame 4, the heater being secured to the boiler by nuts 5". Coverplate 7 is provided with a rubber gasket 8 supported from cross and longitudinal wall members 9, 11 which upwardly project from the mounting plate 3 and form compartments or junction boxes of the desired tube configuration as exemplified in FIG. 6. As shown in FIG. 2, the heater assembly with cover plate 7 can be inserted into aperture 1" of boiler or furnace 1 and is then secured thereto in sealing relation by bolts 5' and nuts 5".

FIG. 2 shows also the V-shaped relation of any two tubes 1, which are interconnected at their lower ends by an elbow 12, which may preferably be provided with a plug 13.

According to the invention, loose helical deflecting means 14 are inserted in tubes 1. These deflecting means may be easily removed after taking off coverplate 7. To increase the intermixing effect deflecting means 14 may be provided with perforations 14', bent-out portions 14" or the like. Further embodiments of deflecting means 14 are illustrated in FIGS. 3 through 5.

In the embodiment shown in FIG. 5, deflecting means 14 come into contact with tube 1 only at certain points 14" thereof, so that here again two flows may interact along the surfaces of the deflecting means in such a manner as to thoroughly mix the fluid stream.

FIG. 6 shows, among others, the connection for the service-water piping. The water to be heated is fed into the heater through pipe 15 and directed through the series-connected tube, after which it leaves the heater by way of pipe 16, connection 17 serving for circulation purposes. As becomes apparent from FIG. 6 also, tubes 1 are readily accessible after removal of cover-plate 7, even when the heater remains installed in the furnace or boiler; hence, the latter need not be drained for a cleaning process.

As experience has shown, deflecting means 14 which, as is indicated in FIG. 2, are in contact with the inner periphery of tubes 1, tend to be retained in place as the tubes become clogged with mineral deposits or the like under adverse operating conditions, unlike such deflecting means as are in contact with the inner walls of the tubes either not at all or at certain points only (FIG. 5). In spite of this fact, such jammed deflecting means present no difficulties in cleaning, because, in accordance with the present invention, they are made from such materials and are of such configuration as to permit the tubes to be cleaned even under the most adverse operating conditions.

Thus, it is well known that deflecting means of rigid construction which are made from relatively heavy gage sheet material and cannot be removed in unscrewing fashion, are most difficult to clean, after they have become wedged, although the mineral deposits themselves can be relatively easily removed by drilling.

In accordance with the present invention, deflecting means 14 are therefore made from light-gage sheet material so that they can be removed, together with the mineral deposits, without impeding the drilling process. Such deflecting means may for instance be made either from heatand liquid-resistant plastic or copper foils, which latter are even more advantageous because they are less expensive than plastic deflectors.

FIG. 7 shows another embodiment of the heater wherein the junction boxes 8, 9, 10, 11 are replaced by fittings 18, 19, 20. This embodiment has the advantage that with a small number of different types of fittings a great variety of heaters of different sizes and designs may be provided. Another advantage is that these fittings including plugs 25 can be manufactured at low cost in quantities by automatic molding processes.

These fittings may have small noses 23 (FIG. 8) meeting each other, when mounted, and capable of being welded or soldered to each other, so that their combination on the mounting plate becomes as rigid and sturdy as if a junction box were used. If a plug 25 is unscrewed to clean a tube, the entire combination of fittings receives the forces applied and generated in the drilling process so that the respective fitting cannot be torn off from tube 1, which might otherwise easily happen, if the fittings were not interconnected as by welding or soldering.

The positions of the fittings 18, 19, 20 as shown in FIG. 7, presents not the least difficulties in the cleaning procedure as the cleaning tools may be mounted on and be driven by flexible shafts. Rather the use of flexible drive shafts permits to employ fittings, whose centerlines or axes are aligned with those of the tubes. In other words, such fittings may be inclined to each other like their associated tubes.

In the configurations shown in FIGS. 7 through 9, the junction boxes illustrated in FIGS. 1, 2, and 6 are completely eliminated by the use of fittings, tubes 1 being arranged in pairs in V-configuration in mounting plate 21 (FIG. 8), so that the entire heater is of compact and flat design. In these embodiments, tubes 1 having fins at their outer periphery extend through drilled holes of suitable size in mounting plate 21, with their free ends 22 being closely connected to fittings 18, 19, and 20. Fittings 18 and 20 are designed to connect to the piping for cold, hot, and circulating water, while fittings 19 are employed to interconnect tubes 1 which, in the illustrated embodiment, are connected in series.

If it is intended to clean tubes 1, the heater with its mounting plate 21 need not be disassembled. Instead, only plugs 25 are removed from fittings 18, 19, and 20, whereupon the cleaning tool may be inserted into the respective tubes. The deflecting means inside the tubes are simply destroyed by the drilling process, if they cannot be unscrewed anymore. Since the tubes are arranged in the shape of a V, the cavity 12 in the elbow 12, which is also shown in FIG. 2, is readily handled by the cleaning tool. The tool advances in the tubes 1 in straight paths which intersect in the elbow cavity so that the connecting portion between the lower ends of the tubes is likewise cleaned.

In FIG. 9, another possible arrangement of tubes is shown. Unlike the configuration in FIG. 8, the pairs of tubes in FIG. 9 are arranged in staggered relationship in mounting plate 21'. This arrangement has the advantage that the number of noses 23 or flats required for interconnecting the fittings can be reduced. Moreover, the constructional height of this heater is still lower than in the other embodiments.

While the novel features of the invention as applied to several preferred embodiments have been shown and described, it will be obvious that modifications of the device illustrated may be made Without departing from the spirit and the scope of the invention. Accordingly, the scope of this invention is to be governed by the language of the following claims construed in the light of the foregoing description of this invention.

What is claimed and desired to be secured by Letters Patent is:

1. A heating apparatus for producing hot water comprising, in combination:

(a) a plurality of straight tube members having respective first and second end portions;

(b) a plurality of coupling members formed with a substantially closed cavity therein,

(1) each coupling member connecting the first end portions of two tube members in communication with said cavity so as to form therewith a V-shaped conduit, and

(2) each tube member of said conduit defining a straight path, the path of each tube member communicating with said cavity intersecting the path of another one of said tube members in said cavity;

(c) mounting plate means for securing said tube members in a furnace;

(d) connecting means connecting respective second end portions of two tube members of respective V- shaped conduits for flow of fluid through said conduits in series; and

(e) removable access means on said second end portions for giving access to each of said straight paths in a straight line.

2. An apparatus as set forth in claim 1, further comprising a removable helical deflecting member in at least one of said tube members,

3. An apparatus as set forth in claim 1, further com prising an outer fin on at least one of said tube members.

4. An apparatus as set forth in claim 1, wherein said connecting means include a plurality of wall members projecting from said mounting plate means and defining a plurality of compartments, each compartment communicating with the connected second end portions, and having a side open in the direction of the paths defined by the associated tube members, said access means including a cover plate common to said compartments and releasably closing said open sides thereof.

5. An apparatus as set forth in claim 1, wherein said connecting means include a plurality of fitting members, each fitting member connecting the second end portions of a tube member of one of said conduits to the second end portion of a tube member of another conduit, and being formed with two openings respectively aligned with the paths defined by the connected two tube members, said access means including removable plug means in each of said openings.

6. An apparatus as set forth in claim 1, wherein said connecting means include a coupling member formed with an opening therein, and said access means include a removable plug member in said opening.

References Cited by the Examiner UNITED STATES PATENTS 662,255 11/00 Davies et al. 122356 1,425,273 8/22 Pabodie 122-32 1,495,065 5/24 Bell 122360 1,796,509 3/31 Daley 12232 1,834,070 12/31 Parkinson 122-32 1,961,744 6/34 Durkee 122501 2,046,569 7/36 Madorin 122379 2,703,072 3/55 Throckmorton et al. 122-33 2,726,643 12/55 Edwards 12233 FOREIGN PATENTS 135,123 11/19 Great Britain.

FREDERICK L. MATIESON, IR., Primary Examiner.

KENNETH W. SPRAGUE, ROBERT A. OLEARY,

Examiners, 

1. A HEATING APPARATUS FOR PRODUCING HOT WATER COMPRISING, IN COMBINATION: (A) A PLURALITY OF STRAIGHT TUBE MEMBERS HAVING RESPECTIVE FIRST AND SECOND END PORTIONS; (B) A PLURALITY OF COUPLING MEMBERS FORMED WITH A SUBSTANTIALLY CLOSED CAVITY THEREIN, (1) EACH COUPLING MEMBER CONNECTING THE FIRST END PORTONS OF TWO TUBE MEMBERS IN COMMUNICATION WITH SAID CAVITY SO AS TO FORM THEREWITH A V-SHAPED CONDUIT, AND (2) EACH TUBE MEMBER OF SAID CONDUIT DEFINING A STRAIGHT PATH, THE PATH OF EACH TUBE MEMBER COMMUNICATING WITH SAID CAVITY INTERSECTING THE PATH OF ANOTHER ONE OF SAID TUBE MEMBERS IN SAID CAVITY; (C) MOUNTING PLATE MEANS FOR SECURING SAID TUBE MEMBERS IN A FURNANCE; (D) CONNECTING MEANS CONNECTING RESPECTIVE SECOND END PORTIONS OF TWO TUBE MEMBERS OF RESPECTIVE VSHAPED CONDUITS FOR FLOW OF FLUID THROUGH SAID CONDUITS IN SERIES; AND (E) REMOVABLE ACCESS MEANS ON SAID SECOND END PORITIONS FOR GIVING ACCESS TO EACH OF SAID STRAIGHT PATHS IN A STRAIGHT LINE. 